1. Field of the Invention
The present invention relates to an application unit that can be used, in particular, in the fields of pharmacy, cosmetics, dermatology, hair care, etc. The invention concerns more particularly a device of the type comprising a solid or semi-solid applicator which must be brought into contact with a liquid composition before its application, and which is capable of solubilizing or gelling on its surface on contact with the liquid composition. By way of example, this may be a lipstick that is but slightly friable and whose surface must be brought into contact with water, for example, in order to soften its surface and to promote the exfoliation of the lip rouge. Again by way of example, the applicator may be of the "styptic pencil" type for cauterizing sores. In this latter application, the applicator contains hydrosoluble active substances, such as mixed sulphates of aluminium and ammonium, which are solubilized in the presence of a liquid composition such as water. The invention also applies to the application of a product which may have a cosmetic effect and a treatment effect, the cosmetic effect being produced by the applicator itself, the treatment effect being obtained by a liquid solution with which the applicator is brought into contact. By way of example, this concerns a lipstick that is brought into contact with a film-forming agent or with a treatment composition of the anti-chapping type. It may also be a stearate soap of ammonium or potassium, or a tensioning stick, for example of polyvinyl alcohol (PVA) capable of effacing wrinkles, or of guar gum. It may also be a compound, such as an emollient, which cannot be introduced into the stick during its manufacture. In general, the invention relates to any friable solid or semi-solid applicator which, before its application to a surface to be treated, has to be brought into contact with a liquid composition permitting its exfoliation, and/or containing active agents that cannot be introduced into the applicator.
2. Description of the Related Art
EP-A-612 488 describes an applicator comprising a reservoir containing a product to be applied, a cap intended to close the reservoir, and an applicator holder supporting a deformable element made of foam or an elastomer of low hardness for the application of the product. The deformable element carries asperities on its surface and is provided with a good (large) shape memory. The product reservoir is delimited by a capillary end fitting, in the form of a glove finger having a bottom that is provided with a seat pierced by at least one capillary opening, against which the deformable element is applied and deformed in the position when the reservoir is closed by the cap.
In the field of lipsticks there exist, moreover, liquid formulas containing polymers, which have the advantage of a long hold on the lips, but which are, in a galenical form, a long way from the established usage of the conventional stick.